Apparatus for reshaping or bending tubular envelopes of fluorescent lamp assemblies into annular form

ABSTRACT

In an apparatus for reshaping or molding tubular envelopes of fluorescent lamps or the like into an annular form, an improvement in or relating to a pulley-shaped mold assembly is disclosed which assembly comprises a pair of separable mold half sections which, when mated together, define an annular groove around the periphery of the mold assembly around which is wrapped an envelope sufficiently heated to a workable or reshapable condition so as to be shaped into the annular form. The molding head of the apparatus comprises two mold assemblies of the type described so that two envelopes may be simultaneously shaped into an annular form. Each mold assembly is divided into a pair of half sections by a vertical plane at right angles to the axis thereof in such a way that one of the half sections located closer to the other mold assembly has a thickness shorter than that of the other half section so that the distance between the paired heads holding tubular envelopes may be shortened with the resultant reduction in overall dimensions of the reshaping apparatus and annular fluorescent lamp manufacturing machine.

United States Patent 1191 Ishisaka [451 Nov. 18, 1975 154] APPARATUS FOR RESHAPING OR BENDING TUBULAR ENVELOPES OF FLUORESCENT LAMP ASSEMBLIES INTO ANNULAR FORM [75] lnventor: Tsutomu Ishisaka, Takatsuki, Japan [73] Assignee: Matsushita Electronics Corporation,

Osaka, Japan 22 Filed: July 24, 1974 21 Appl. No.: 491,271

[30] Foreign Application Priority Data Primary Examiner-Arthur D. Kellogg Attorney, Agent, or Firm-Burgess, Ryan and Wayne [57] ABSTRACT In an apparatus for reshaping or molding tubular envelopes of fluorescent lamps or the like into.an annular form, an improvement in or relating to a pulleyshaped mold assembly is disclosed which assembly comprises a pair of separable mold half sections which, when mated together, define an annular groove around the periphery of the mold assembly around which is wrapped an envelope sufficiently heated to a workable or reshapable condition so as to be shaped into the annular form. The molding head of the apparatus comprises two mold assemblies of the type described so that two envelopes may be simultaneously shaped into an annular form. Each mold assembly is divided into a pair of half sections by a vertical plane at right angles to the axis thereof in such a way that one of the half sections located closer to the other mold assembly has a thickness shorter than that of the other half section so that the distance between the paired heads holding tubular envelopes may be shortened with the resultant reduction in overall dimensions of the reshaping apparatus and annular fluorescent lamp manufacturing machine.

1 Claim, 5 Drawing Figures US. Patent Nov. 18,1975 Sheet 1 of2 3,920,434

FIG. 3

FIG. I

FIG. 4

FIG. 2

US. Patent Nov. 18, 1975 Sheet20f2 5o 48' 54 e o BACKGROUND OF THE PRESENT INVENTION The present invention relates generally to an apparatus for reshaping or molding rectilinear envelopes of fluorescent lamps or the like into an annular form, and more particularly a molding head thereof provided with a pair of pulley-shaped mold assemblies around which are wrapped tubular envelopes sufficiently heated to a workable or moldable condition so as to reshape 'or mold them into the annular form.

According to the prior art methods and apparatus of the type described, a fluorescent lamp assembly, consisting of a substantially rectilinear tubular envelope with a fluorescent coating on its inner wall and metal caps, or mounts fitted over the ends of the envelope, is heated, softened, and wrapped around the periphery of a pulley-shaped mold assembly, so as to be reshaped or molded into an annular form. In general, the pulleyshaped mold assembly comprises a pair of separable" mold half sections, or halves, which, when mated, define an annular groove substantially semi-circular in cross sectional configuration around the periphery of around the mold assembly is cooled and hardened to some extent, the halves are separated from each other to permit the removal of the reshaped annular envelope from the mold assembly.

In the prior art apparatus of the type used for bending and exhausting tubular lamps, only one head which holdsan envelope is moved or transferred from one work station to the next. In other words, one head takes one station. Therefore, there has been no problem even when the mold assembly of the type described has been used. However, in order to increase the productivity in the manufacture of fluorescent lamps or the like, it has, been proposed to attach two coaxial mold assemblies on each reshaping apparatus so that two envelopes may be simultaneously reshaped into an annular form at a reshaping station. It is preferable that the distance between the two envelopes being reshaped by the mold assemblies be made as small as practically possible in order to make the annular fluorescent lamp manufacturing apparatus compact in size, and to increase the production efficiency, especially when successive operations such as heating, reshaping, exhausting, filling inert gas into envelopes and so on are carried out at various stations located around the circular traveling path of-a plurality of heads which are moved or transferred from one station to the next by a turret or the like. That is, in a conventional rotary type apparatus for bending and exhausting tubular lamps, a plurality of heads adapted to hold tubular lamps are generally radially and equiangularly attached to a driving shaft, and are intermittently moved from one station to the next, so that the above described successive operations may be effected at successive stations. i

When the lamp manufacturing apparatus of the type described is so improved that two heads may he simultaneously moved from one station to the next station, whereby two envelopes held by the two heads, respectively, may undergo the same operation simulta ncously, the apparatus may be made compact in size and the productivity may be considerably improved. However, when the distance between the axes of the two lamps held by the heads is long. the radius of the manufacturing apparatus also becomes long so that the space for installation of the apparatus must he increased. Furthermore the apparatus itself becomes heavy so that the indexing of the heads becomes very difficult. Therefore, it is very important that the distance between the axes of the envelopes or tubular lamps held by the heads must be reduced as much as possible so that a manufacturing apparatus both compact in size and light in weight may be provided.

SUMMARY OF THE INVENTION One of the objects of the present invention is to provide a fluorescent lamp manufacturing machine or apparatus with an improved apparatus for reshaping tubular envelopes of fluorescent lamps into a annular form.

Another object of the present invention is to provide the reshaping apparatus of the type described provided with two pulley-shaped mold assemblies around which is wrapped envelopes heated to a workable or moldable temperature so as to be reshaped or molded into annular form, the two mold assemblies being so coaxially arrangedas to reduce the distance therebetween as much as possible, each mold assembly comprising a pair of mold half sections separable from each other at a parting plane at right angles to the axis of the mold assembly.

A further object of the present invention is to provide the apparatus of the type described, in which each I mold assembly is divided into a pair of half sections by the vertical parting plane at right angles to the axis thereof and spaced apart by a predetermined distance from the conventional parting plane through the midpoint of the axial length of the mold assembly so that the distance between the axes of the tubular envelopes wrapped into the grooves defined by the half section may be minimized as much as possible.

According to the present invention, therefore, the

distance between the axes of two tubular envelopes being reshaped may be minimized so that the fluorescent lamp manufacturing machine or apparatus may be made compact in size and light in weight, the installation space may be reduced, and the power consumption for rotating the machine may be minimized with the resultant reduction in operation cost.

The above and other objects and features of the present invention will become more apparent from the following description of one preferred embodiment thereof taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a diagrammatic top view of an annular fluorescent lamp manufacturing machine or apparatus incorporating therein a tubular lamp reshaping apparatus in accordance with the present invention;

FIG. 2 is a fragmentary side view of a head for holding a tubular envelope;

3 FIG. 3 is a schematic side view of one preferred embodiment of a tubular envelope reshaping apparatus in accordance with the present invention;

FIG. 4 is a sectional view taken along the line AA of FIG. 3; and

FIG. is a top view of a mold head thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENT An apparatus for manufacture of annular fluorescent lamps incorporates an apparatus 12 in accordance with the present invention for reshaping rectilinear tubular lamp envelopes into annular form is shown diagrammatically in FIG. 1, and comprises a base 1, a turret 3 which is rotated by a drive shaft 2 vertically extending coaxially of the base 1, a plurality of paired heads 4 and 4' carried by the turret 3 in equiangularly spaced apart relation, and adapted to be intermittently transferred from one working station to the next as the turret 3 is indexed, and various devices and apparatus disposed at working stations (not shown except the reshaping apparatus 12) for effecting heating, exhausting or evacuation of, filling gases into lamp envelopes, reshaping envelopes and so onv According to the present invention, the two heads 4 and 4' are paired so that two lamp envelopes held by them may be simultaneously processed at each working station.

Each head comprises, as shown in FIG. 2, a holder 7 adapted to grip and support one end of the envelope 6 ofa fluorescent lamp 5, and an exhaust head 9 to which is coupled an exhaust tube 8 extending from the envelope 6 so as to exhaust or evacuate it. The holder 7 is adapted to grip an upper reduced-diameter end portion or a metal cap fitted on of the lamp 5 so as to support it as it undergoes various operations. The exhaust head 9 is located radially inwardly of the axis of the envelope 6, and the exhaust tube 8 is so bent as to be coupled to the exhaust head 9. The head 4 of the type above is described in detail in, for instance, US. Pat. No. 2,494,923, entitled Method and Apparatus for Bending and Exhausting Tubular Lamps," granted to Joe Yoder et al., Jan. 17, I950.

The fluorescent lamp 5, which has a rectilinear envelope 6 and metal caps fitted over the upper end and the lower reduced-diameter end portions thereof, as gripped and supported by the holders 7 of the heads 4 and 4 at one of the working stations, and are intermittently transferred from one working station to the next as the turret 3 is rotated and indexed in the counterclockwise direction. In the successive working stations, the envelopes 6 are exhausted, filled with nitrogen gas, heated in ovens at more than two stations, reshaped into the annular form by the reshaping apparatus 12 in accordance with the present invention when they are heated sufficiently to a workable or reshapable temperature, thereafter heated and exhausted again, filled with mercury and argon gases, and finally released from the holders 7 after the exhaust tubes 8 are cut off. Thus the bending and exhaust or evacuation of the envelopes 6 are accomplished.

The reshaping apparatus 12 of the present invention is located at the inoperative position which in turn is located radially outwardly of the path 13 of the heads 4 and 4' as shown in FIG. 1 when the heads 4 and 4 are transferred from one working station to the next, but the reshaping apparatus 12 is advanced into the operative position radially inwardly as will be described in 4 detail hereinafter so as to bend the envelopes 6 into the annular form.

Next referring to FIGS. 3, 4 and 5 the reshaping apparatus 12 of the present invention will be described in detail hereinafter, The apparatus 12 generally comprises, as shown in FIGS. 3 and 4, a base 14, a top plate 17 supported by four upright columns l5, l5, l6 and 16' extending from the base 14, and a mold head 18 slidably fitted over the front upright columns 15 and 15. That is, the front upright columns 15 and 15 are slidably fitted into through bores 19 and 19', respectively, of the mold head 18. The mold assembly or head 18 is coupled to a counter balance or weight (not shown) slidably fitted over the rear upright columns 16 and 16 with a chain (not shown) whose both ends are firmly fastened to the tops of the mold head 18 and the counter balance or weight, respectively, and which are wrapped partly around sprockets (not shown) attached to the top plate 17. Therefore the upward and down ward movements of the mold head 18 may be balanced by the downward and upward movements of the counter balance or weight, respectively. One end of another chain 20 is firmly fastened to the top of the mold head 18 while the other end thereof is fastened to the bottom or undersurface of the mold head 18. The chain 20 is wrapped around driven sprockets 21 and 22 attached to the top plate 17, a driving sprocket 23 and a driven sprocket 24 rotatably journaled to bearings or journals (not shown) which in turn are attached to the base 14. The driving sprocket 23 rotates in synchronism with the transfer and dwelling of the heads 4 and 4, thereby causing the upward or downward movement of the mold head 18 as will be described in more detail hereinafter. The reshaping apparatus 12 is mounted upon a carriage (not shown) so as to be moved radially inwardly or outwardly from the inoperative position to the operative position or vice versa in synchronism with the indexing rotation of the turret 3.

Next referring to FIG. 5, the mold head 18 will be described in detail hereinafter. Two pulley-shaped mold assemblies 28 and 29 whose construction will be described in more detail hereinafter are rotatably and coaxially carried by shafts 37 and 37 and 38 and 38, respectively, which in turn are journalled to journals or bearings 25, 26 and 27 attached to the front surface of the mold head 18. The shafts 37 and 38 of the mold assemblies 28 and 29 are supported by the common journal 26. The mold assemblies 28 and 29 have annular grooves 30 and 31 semi-circular in cross sectonal configuration formed around the peripheries thereof, and are comprised of a pair of half sections 35 and 35' and a pair of half sections 36 and 36', respectively. The opposing or mating surfaces, of the half sections 35 and 35 to or 36 and 36 to mate or are brought into intimate contact with each other over the vertical parting plane 33 or 34 spaced apart toward the adjacent mold assembly 29 or 28 by a distance 6 from the vertical plane 55 or 56 through the midpoint of the mold assembly 28 or 29 and through the axis of the envelope 6 wrapped around the mold assembly 28 or 29 in its groove 30 or 31. These half sections 35, 35', 36 and 36 are carried, in a cantilever-like manner, by the shafts 37, 37', 38 and 38', respectively, whose ends remote from their journaled end portions are coplanar with the mating surfaces of the half sections 35, 35, 36 and 36',

respectively. The shaft 37' carrying the half section 35' I is internally splined while the shaft 38 carrying the half section 36 is splined outwards so that they rotate in unison when the splines mates.

A A small-di-ameterpullcy. 39 and a gear 41, which are made integral with each other, are also carried by the 'of the half section 36. The reason why no gear is carried by the shaft 38 is :thatthe, latter may be splined to the shaft 37 for rotation in unison therewith when the gear 41' cat'ried by the shaft 38 is driven. The shafts 37, 37", 38 and 38 are slightly movable in the direction of their common axis 32 so that the half sections 35 and 35' and 36 and 36 may be mated together to form the annular grooves 30 and 31 along with the tubular envelopes 6 are reshaped into the annular form and so that the half sections 35 and 35' and 36 and 36' may be separated from each other so as to permit the removal of the reshaped annular envelopes 6 from the mold assemblies 28 and 29.

The driven gears 41, 41' and 42 are in mesh with driving pinions 43, 44 and 45, respectively, attached on the front surface of the mold head 18 in such a manner that their engagements may be maintained even when the shafts 37, 37 and 38' and hence the gears 41, 41 and 42 are axially moved. These pinions 43, 44 and 45 are drivingly coupled to a drive mechanism (not shown) so that they may be driven in synchronism with the upward movement of the mold head 18. Consequently the mold assemblies 28 and 29 are rotated so that the envelopes 6 are wrapped around them in their grooves 30 and 31.

Two linkages 46 and 47, which are substantially similar in arrangement, are provided for the mold assemblies 28 and 29, respectively, and it will suffice to describe the arrangement and mode of operation of only the left linkage 46 for the mold assembly 28. The linkage 46 comprises a pair of long link-bars or levers 48 and 48 pivoted on the mold head 18 at 50 and 50', respectively, and a pair of short link-bars or levers 49 and 49 whose outer ends are pivoted to one of the lower ends of the long levers 48 and 48' at 52 and 52', respectively, and whose inner ends are pivoted on one end of 6 terclockwise direction thus causing the downward movement of the common pivot point 53 of the short levers 49 and 49'. Consequently the pivots 52 and 52' are moved away from each other so thatthe first long lever 48 swings about its pivot 50in the clockwise direction while the second long lever 48 swings in the counterclockwise direction about its pivot 50'. Asa result, the pins 51 and 51 of the long levers 48 and 48 V aremoved toward each other so as to cause the separated half sections 35 and 35 of the mold assembly 28 .to mate together to define the annular molding groove while the pinions 43, 44 and 45 (see FIG. 5) are also an actuating lever 54 with a common pivot pin 53. Pins 51 and 51 extended form the other or upper ends of the long levers 48 and 48 are fitted into the grooves of the small-diameter pullies 39 and 39', respectively. It should be noted that the distance between the pin 51 and the pivot point of a first of the long levers 48 is longer than that between the pin 51 and the pivot point 50 of a second of the other long levers 48 so that it is apparent that the pin 51 of the upper and of the first long lever 48 is caused to be displaced over a longer distance than the pin 51 of the upper and of the second long lever 48 when the actuating lever 54 swings about its pivot point.

Next the mode of operation will be described in detail hereinafter. Referring back to FIG. 1, when the heads 4 and 4' which hold sufficiently softened envelopes 6 are transferred to the station 11, the reshaping apparatus 12 of the present invention is caused to move from its inoperative position to the operative position in the manner described hereinbefore. As soon as the apparatus 12 takes its operative position, the actuating lever 54 (see FIG. 5) swings about its pivot in the coundriven to drive the gears 41, 41' and 42. Consequently, the mold assembly 28 is rotated so that the envelope 6 is wrapped therearound in its groove 30. When the envelope 6 is completely wrapped around the mold assembly 28, the upward movement of the mold head 18 is stopped. After a short time required to permit the reshaped envelope 6 to be cooled and hardened again, the actuating lever 54 swings in the clockwise direction about its pivot point so that the pins 51 and 51' at the upper ends of the long levers 48 and 48' are caused to move away from each other. As a result, the half sections 35 and 35' of the mold assembly 28 are separated from each other in the axial direction. Then the apparatus 12 is retracted to its inoperative position so that the I reshaped annular envelope held by the head 4 may be transferred from the reshaping station to the next station. As soon as the apparatus 12 takes the inoperative position, the driving sprocket 23 is driven in the reversed direction to cause the downward movement of the mold head 18 to its initial position.

In the conventional reshaping apparatus, each mold assembly comprises a pair of half sections equal in thickness which are cuased to move away from each other in the axial direction over a distance equal to one half of the envelope 6. However, according to the present invention, the half sections 35 and 35' of the mold assembly 28 are different in thickness. That is, the half section 35' on the side of the adjacent mold assembly 29 has a thickness smaller by 6 than the half section 35 as described hereinbefore. This means that the axial displacement of the half section 35' away from the half section 35 is shorter by e than that of the corresponding half section of the prior art mold assembly. Therefore the distance between the axes of the envelopes 6 held by the paired heads 4 and 4' may be shorter by 26 than the corresponding distance in the prior art apparatus. However, the outer half sections 35 and 35' must be displaced over a distance longer by e than the corresponding distance in the prior art apparatus, but it is readily understood that the increase in displacement or stroke of the outer half sections will by no means adversely affect the arrangement, construction and operation of the reshaping apparatus of the present invention.

According to the present invention, as described hereinbefore, the distance between the adjacent envelopes of the fluorescent lamps held by the paired heads 7 may be shortened by 2e over the corresponding distance in the prior art apparatus. Therefore, in case of the apparatus having, for instance, 30 heads, the traveling path of the heads may be shortened by 606. In other words, the diameter of the circular traveling path may be shorted by 60 6/11.

What is claimed is:

1. In an apparatus for reshaping two rectilinear envelopes'of fluorescent lamp assemblies into an annular form, the apparatus having two pulley-shaped mold assemblies having annular grooves around the peripheries thereof for wrapping rectilinear envelopes of fluorescent lamp assemblies, each of said mold assemblies comprising a pair of half sections divided by vertical parting planes at right angles to the axes of said mold assemblies, said mold assemblies being mounted in a retaining structure in a position wherein one half of each mold assembly faces a corresponding half of the other mold assembly and is adjacent thereto,

the improvement wherein mold assembly, whereby one of said half sections of each mold assembly is thinner in the axial direction than the other half section,

wherein the thinner half sections of each mold assembly are those corresponding halves of each mold assembly that are mounted adjacent each other in the retaining structure, and wherein the distance between said corresponding thinner half sections of said mold assemblies is sufficient only to permit opening of said mold assemblies and removal of said fluorescent lamp assemblies,

whereby the axial displacement of said thinner half sections for removal of said fluorescent lamp assemblies is shortened by a distance equal to one half of the difference in thickness between each of said pairs of half sections as compared with the corresponding distance when said half sections are symmetrically divided.

UNITED STATES PATENT OFFICE CETEFICATE OF CORRECTION Patent 3,920,434 Dated November 18, 1975 Inventor(s) Tsutomu IShiSaka It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 46: Change "as" to are- Column 4, line 53; After "surfaces" cancel the comma.

line 54: Cancel "to" (both occurrences) Column 5, line 1: Change "mates" to mate-.

line 18: Change "with" to --which-.

Signed and Sealed this eleventh Of May 1976 [SEAL] A nest.-

RUTH C. MASON C. MARSHALL DANN .-l!rm!mg ()ljm-r ('mnmissium'r nj'larz'ms and Trm/vmurkX 

1. IN AN APPARATUS FOR RESHAPING TWO RECTILINEAR ENEVELOPES OF FLUORESCENT LAMP ASSEMBLIES INTO AN ANNULAR FORM, THE APPARATUS HAVING TWO PULLEY-SHAPED MOLD ASSEMBLIES HAVING ANNULAR GROOVES AROUND THE PERIPHERIES THEREOF FOR WRAPPING RECTILINEAR ENVELOPES OF FLUORESCENT LAMP ASSEMBLIES EACH OF SAID MOLD ASSEMBLIES COMPRISING A PAIR OF HALF SECTIONS DIVIDED BY VERTICAL PARTING PLANES AT RIGHT ANGLES TO THE AXES OF SAID MOLD ASSEMBLIES SAID MOLD ASSEMBLIES BEING MOUNTED IN A RETAINING STRUCTURE IN A POSITION WHEREIN ONE HALF OF OF EACH MOLD ASSEMBLY FACES A CORRESPONDING HALF OF THE OTHER MOLD ASSEMBLY AND IS ADJACENT THERETO, THE IMPROVEMENT WHEREIN SAID VERTICAL PARTING PLANES ASYMMETRICALLY DIVIDE THE MOLD ASSEMBLY, WHEREBY F SECTIONS OF EACH MOLD ASSEMBLY IS THINNER IN THE AXIAL DIRECTION THAN THE OTHER HALF SECTION, WHEREIN THE THINNER HALF SECTIONS OF EACH MOLD ASSEMBLY ARE THOSE CORRESPONDING HALVES OF EACH MOLD ASSEMBLY THAT ARE MOUNTED ADJACENT EACH OTHER IN THE RETAINING STRUCTURE, AND WHEREIN THE DISTANCE BETWEEN SAID CORRESPONDING THINNER HALF SECTIONA OF SAID MOLD ASSEMBLIES IS SUFFICIENT ONLY TO PERMIT OPENING OF SAID MOLD ASSEMBLIES AND REMOVAL OF SAID FLUORESCENT LAMP ASSEMBLIES WHEREBY THE AXIAL DISPLACEMENT OF SAID THINNER HALF SECTION FOR REMOVAL OF SAID FLUORESCENT LAMP ASSEMBLIES IS SHORTENDED BY A DISTANCE EQUAL TO ONE HALF OF THE DIFFERENCE IN THICKNESS BETWEEN EACH OF SAID PAIRS OF HALF SECTIONS AS COMPARED WITH THE CORRESPONDING DISTANCE WHEN SAID HALF SECTIONS ARE SYMMETRICALLY DIVIDED. 